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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Frank van der Linden , linux-mm@kvack.org, linux-kernel@vger.kernel.org, muchun.song@linux.dev, Muchun Song Subject: [PATCH] mm/sparse: fix preinited section_mem_map clobbering on failure path Date: Tue, 31 Mar 2026 19:37:24 +0800 Message-Id: <20260331113724.2080833-1-songmuchun@bytedance.com> X-Mailer: git-send-email 2.20.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" sparse_init_nid() is careful to leave alone every section whose vmemmap has already been set up by sparse_vmemmap_init_nid_early(); it only clears section_mem_map for the rest: if (!preinited_vmemmap_section(ms)) ms->section_mem_map =3D 0; A leftover line after that conditional block ms->section_mem_map =3D 0; was supposed to be deleted but was missed in the failure path, causing the field to be overwritten for all sections when memory allocation fails, effectively destroying the pre-initialization check. Drop the stray assignment so that preinited sections retain their already valid state. Fixes: d65917c42373 ("mm/sparse: allow for alternate vmemmap section init a= t boot") Signed-off-by: Muchun Song Acked-by: David Hildenbrand (Arm) --- mm/sparse.c | 1 - 1 file changed, 1 deletion(-) diff --git a/mm/sparse.c b/mm/sparse.c index c2eb36bfb86d..3a14b733bf71 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -584,7 +584,6 @@ static void __init sparse_init_nid(int nid, unsigned lo= ng pnum_begin, ms =3D __nr_to_section(pnum); if (!preinited_vmemmap_section(ms)) ms->section_mem_map =3D 0; - ms->section_mem_map =3D 0; } } =20 --=20 2.20.1